Piston compressor, especially for refrigeration



M. CLAUSEN Aug. 24, 1965 PISTON COMPRESSOR, ESPECIALLY FOR REFRIGERATION Filed Aug. 10, 1962 United States Patent "ice 3,2ti2,344 PlSTON COMPRESSGR, EPECIALLY FUR REFMGERATIUN Mails Ciausen, Elsrnark, Nordborg, Denmark, assignor to Danfoss ved Tug. M. Clausen, Nordborg, Denmark, a

company of Denmark Filed Aug. 10, 1962, Ser. No. 216,708 3 Claims. (Cl. 230-232) This invention relates to piston compressors and is more particularly concerned with piston compressors of the type especially adapted for use in small refrigerating machines.

It is a continuing goal of manufacturers of small-sized and mass-produced piston compressors, commonly used in the form of hermetically sealed compressors for small refrigerating machines, to produce such compressors of as few and of as non-complicated components as possible. It is, therefore, customary to combine the cylinder and at least two silencing chambers in one casting. In this manner, at both sides of the cylinder there is provided a chamber, or a group of chambers, one of which acts as a suction mufiier and the other as a pressure mufiier.

If it is essential to obtain effective silencing, this construction is inconvenient because the casting is suited for one single compressor type only. If one or another of the factors determining the compressor type, e.g. the diameter of the cylinder bore, the stroke length, the number of strokes per unit time, or the specific gravity of the refrigerant to be compressed (for example by using a different refrigerant), is changed, the effective silencing automatically is reduced because the muffler system remains unchanged.

On the other hand, it is not possible, even by maintaining the above-mentioned factors constant, to improve the silencing effect if special circumstances require this to be done.

It is, accordingly, an object of this invention to provide a compressor construction which avoids the drawbacks and disadvantages of prior constructions.

It is a further object of the invention to provide a construction of the character indicated which permits maximum silencing to be achieved under all conditions.

In accordance with the present invention a construction is provided which makes it possible to utilize the same casting for a number of different piston compressor types wherein at least one chamber is connected as a suction silencing chamber for at least one predetermined type, and as a pressure silencing chamber for at least one other predetermined type.

The construction of the invention is, according to the preferred embodiment of the invention, characterized by the fact that the chambers located on both sides of the cylinder are connected with each other.

In this manner, even with only two chamber, it is possible to adapt the silencing system to several compressor types. For example, for one type, the two chambers are connected as suctionand pressure-silencing cham bars, for a second type the two chambers are connected as parallel-connected suction-silencing chambers, and for a third type the two chambers are connected as series connected suction-silencing chambers. In most cases the two latter mentioned types may require a pressure muffler which, however, does not cause any difficulties and is considerably cheaper to manufacture than is a special casting for each compressor type.

It is, of course, possible to use the two chambers as pressure mufflers connected either in parallel or in series. Their use as suction mufi'lers is, however, preferred because of thermal conditions and because of ease of effecting connection, viz simply by means of a bore to the dfihzfi i i ?atented Aug. 24, 1965 suction chamber. When use is made of more than two chambers, the connection possibilities are increased considerably. In this case, it is possible not only to combine two groups of chambers in the manner described above for two single chambers but also, for example, to connect, either in parallel or in series, some of the chambers located on one side of the cylinder with all the chamberslocated on the other side of the cylinder. If three or more chambers are available for a muilier, it is also possible to use a series-parallel connection.

It is further possible to adapt the silencing system to certain compressor types by coupling a series-connected chamber, composed of at least two succeeding suction silencing chambers, by means of a channel leading directly to the suction chamber. It is also possible to obtain certain advantages when the inlet and/ or the outlet-channel for at least one chamber is formed by means of a tube inserted in a bore, with the cross section and/ or length of the tube being adapted for the particular conditions required.

When connecting the two suction silencing chambers in series, it is usually necessary to employ a supplementary connecting line or bore. When connecting in parallel, however, it is possible to avoid the useof supplementary elements by joining the two systems in the suction valve chamber located in the cylinder cover. In this case, it is advantageous to connect, by means of two bores, the chambers located on both sides of the cylinder with the front side of the casting, thus enabling the cylinder cover, which can be placed in either of two opposite positions, viz in a first position to separate the two bores by means of its cross wall, and in a second position to lead the bores directly into the suction valve chamber.

By means of a simple displacement of the cylinder cover and change in the pressure line inlet, the normal arrangement provided with suction silencing chambers and pressure silencing chambers on the cylinder sides is readily converted into an arrangement provided with two parallel-connected suction silencing chambers.

Further characteristics of this invention. will be ap parent from the following description of several embodiments thereof, taken in connection with the accompanying drawings, wherein:

FIG. 1 is a cross-sectional view of the cylinder head of a piston compressor;

FIG. 2 is a similar cross-sectional view of a first modified embodiment in accordance with the invention;

FIG. 3 is a cross-sectional view of a second modified embodiment of the invention; and

FIG. 4 is a fragmentary front elevational View of the casting of FIGS. 1 and 2, in which line A--A indicates the sectional line for these figures.

Referring to FIG. 1, the compressor body casting 1 is formed with the cylinder bore 2, with the silencing chambers 3 and 4- on one side, and with the silencing chambers 5 and 6 on the other side. The forward end 7 of the bore 2 is-covered by a valve plate 8 containing the suction valve 9 and the pressure valve 10. The cylinder cover 11 is placed on top of the valve plate 8 and contains the suction valve chamber 12. and the pressure valve chamber 13, which are separated by means of the cross wall 14. Bores 15, 16, 17, 13, 19 and 28 provide connection among the chambers. The valve plate comprises ports positionable in communication with the passageways 17 and 18.

In the arrangement shown in FIG. 1, chambers 3 and 4 are suction-silencing chambers and chambers 5 and 6 are pressure-silencing chambers, and they are connected in series. The gaseous refrigerant passes through the inlet bore 15, the chamber 3, the connecting bore 17 and the suction valve chamber 12 of cylinder 2 and,

after compression, continues through pressure valve chamber if, the connecting bore 18, the chamber 5, the connecting bore 19, the chamber 6, and the outlet bore 20 to which the pressure line is connected.

In FIG. 2, the compressor body casting ll is constructed for a larger stroke volume. The cylinder bore 2 has a greater diameter than bore 2 of FIG. 1. In this case, all chambers from 3' to 6 are parallel-connected in pairs and act as a suction muffler.

The refrigerant is supplied through the separate bores and and is re-united in the suction valve chamber 12. In this case, the pressure line is connected by means of a connection 21 directly with the pressure valve chamber 13'. As shown in FIG. 4, the connecting bores, or their extensions, terminate outside the center of the valve plate 8 which is disposed on the front surface 7' of the cylinder. If the cylinder cover is positioned so that the separating wall 14 runs along the line BB, the bores are separated by means of this cross wall, as in FIG. 1. When the cross wall 14 runs along the line C-C, both bores terminate in the suction valve chamber, as in FIG. 2.

7 According to the construction shown in FIG. 3, the four chambers 3 and 6" are connected in series as a suction muffler. To achieve this relationship it is only necessary, with respect to the construction shown in FIG. 1, to replace the bore 13 with an inlet bore 22", to connect the bores 20 and 15 with a tube 23", and to connect the pressure line with the port 21". Furthermore, the shaded areas in FIG. 3 show where the simple bores in the Wall of the casting can be replaced with tubes 24" having a predetermined length and cross section, and the shaded areas also show a short circuitbore 25 which makes it possible to obtain a still better adaption of the silencing system.

It will be apparent that the cylinder head illustrated is adapted to be filled with a piston in conventional manner and that the piston is adapted to be reciprocated by any conventional means. The invention is not com cerned with these components, however, and they have thus been omitted to facilitate the description of the invention.

It will also be understood that various changes and modifications may be made in the embodiments herein described without departing from the scope of the invention as defined in the appended claims. It is-intended, therefore, that all matter contained in the foregoing description and in the drawings shall be interpreted as illustrative only and not as limitative of the invention.

What I claim is:

1. In a process for producing a plurality of piston compressors of different types, particularly for use in small refrigerating machines of different ratings, the steps of forming a plurality of like compressor body castings, each being formed with a front face, a compressor cylinder opening in said face and at least one silencing chamber on each of opposite sides of said cylinder, forming passages connecting a respective chamber on each side of said cylinder with said front face, machining said cylinders to selected different sizes forming a plurality of valve units fitting over the front ends of said cylinders, each valve unit being formed with an inlet valve and a discharge valve, forming a plurality of covers each with two cavities separated by a partition, securing said covers on said front faces of said castings overlying said valve units, with one cavity of each of the covers positioned to provide communication between the chamber on one side of said cylinders and the inlet valve and the other cavity of each of said covers positioned to provide cornmunication between a chamber on the opposite side of said cylinder and the discharge valve, and with a cavity of each of other selected covers positioned to provide communications between said inlet valve and chambers on opposite sides of said cylinder, whereby compressors of different ratings and characteristics are produced from like castings.

2. In a process for producing a plurality of piston compressors of different types, particularly for use in small refrigerating machines of different ratings, the steps of forming a plurality of like compressor body castings, each being formed with a front face, a compressor cylinder opening in said face and at least twosilencing chambers on each of opposite sides of said cylinder forming a passage connecting at least one chamber on a side of said cylinder with said front face, machining said cylinders to selected different sizes, forming a plurality of valve units fitting over the front ends of respective cylinders, each valve unit being formed with an inlet valve and a discharge valve, forming a plurality of covers each with two cavities separated by a partition, securing said covers on said front faces of said castings over said valve units, with one cavity of each of selected covers positioned to provide communication between said inlet valve and said passage connecting a chamber on one side of said cylinder with said front face and the other cavity of each said selected covers positioned to provide communication to said discharge valve, and in some castings establishing series communication be tween a chamber on one side of said cylinder and a chamber on the opposite side comprising said one chamber, whereby compressors of different ratings and characteristics are produced from like castings.

3. In a process for producing a plurality of piston compressors of different characteristics, particularly for sealed refrigerating units, the steps of forming a plurality of substantially identical castings, each being formed with a front face, a compressor cylinder opening in said face and at least two silencing chambers on each of opposite sides of said cylinder, forming a passage connecting a chamber on each side of said cylinder with said front face, said passages being offset from a plane passing through the'axis of said cylinder, forming other passages connecting said chambers with one another and connecting at least one of said chambers with the exterior of said casting, forming a plurality of valve units fitting over the front ends of said cylinders, each valve unit being formed with an inlet valve and a discharge valve, forming a plurality of covers each with two cavities separated by a partition, securing said covers on said front faces of said castings over said valve units, with one cavity of each of selected covers positioned to provide communication between said inlet valve and a passage connecting a chamber on one side of said cylinder with said front face and the other cavity of each of said selected covers positioned to provide communication between said discharge valve and a passage connecting a chamber on the opposite side of said cylinder with said front face, and with a cavity of each of other selected covers positioned to provide communication between said inlet valve and cavities on opposite sides of said cylinder, whereby compressors of difierent characteristics are produced from substantially identical castings.

References Cited by the Examiner UNITED STATES PATENTS DONLEY J. STOCKING, Primary Examiner.

JOSEPH H. BRANSON, 1a., KARL J. ALBRECHT,

Examiners. 

1. IN A PROCESS FOR PRODUCING A PLURALITY OF PISTON COMPRESSORS OF DIFFERENT TYPES, PARTICULARLY FOR USE IN SMALL REFRIGERATING MACHINES OF DIFFERENT RATINGS, THE STEPS OF FORMING A PLURALITY OF LIKE COMPRESSOR BODY CASTINGS, EACH BEING FORMED WITH A FRONT FACE, A COMPRESSOR CYLINDER OPENING IN SAID FACE AND AT LEAST ONE SILENCING CHAMBER ON EACH OF OPPOSITE SIDES OF SAID CYLINDER, FORMING PASSAGES CONNECTING A RESPECTIVE CHAMBER ON EACH SIDE OF SAID CYLINDER WITH SAID FRONT FACE, MACHINING SAID CYLINDERS TO SELECTED DIFFERENT SIZES FORMING A PLURALITY OF VALVE UNITS FITTING OVER THE FRONT ENDS OF SAID CYLINDERS, EACH VALVE UNIT BEING FORMED WITH AN INLET VALVE AND A DISCHARGE VALVE, FORMING A PLURALITY OF COVERS EACH WITH TWO CAVITIES SEPARATED BY A PARTITION, SECURING SAID COVERS ON SAID FRONT FACES OF SAID CASTING S OVERLYING SAID VALVE UNITS, WITH ONE CAVITY OF EACH OF THE COVERS POSITIONED TO PROVIDE COMMUNICATION BETWEEN THE CHAMBER ON ONE SIDE OF SAID CYLINDERS AND THE INLET VALVE AND THE OTHER CAVITY OF EACH OF SAID COVERS POSITIONED TO PROVIDE COMMUNICATION BETWEEN A CHAMBER ON THE OPPOSITE SIDE OF SAID CYLINDER AND THE DISCHARGE VALVE, AND WITH A CAVITY OF EACH OF OTHER SELECTED COVERS POSITIONED TO PROVIDE COMMUNICATIONS BETWEEN SAID INLET VALVE AND CHAMBERS ON OPPOSITE SIDES OF SAID CYLINDER, WHEREBY COMPRESSORS OF DIFFERENT RATINGS AND CHARACTERISTICS ARE PRODUCED FROM LIKE CASTINGS. 